I think it is better to stay online, because it seems that (in Sydney) from what I see, the pings are shared across the online driver pool with an hourly gross rate of around $30-35 per hour (so something like $18 in reality).

So by staying online you can use up "dead-quota-time" while repositioning.

And if you get a ping, accept it and just ignore it. Pax will cancel when they see you going well off course, they can't rate you - so it's all good.